html, body { height: 100%; }

body { margin: 0; }

#root-window { height: 100%; }

#render-target {
  position: relative;
  height: 100%;
}

#ui-toolbar {
  position: absolute;
  width: 150px;
  height: 100vh;
  padding: 16px;
  background-color: #00000033;
}

.ui-button {
  width: 100%;
  height: 40px;
  border: 1px solid black;
  margin: 4px 0;
  text-transform: uppercase;
  font-size: 16px;;
  color: lightgray;
  background-color: #00000055;
}

.ui-button.selected {
  background-color: #55558855;
}

.ui-button:not(.selected):hover {
  background-color: #33333355;;
}
